Lighting device for dental and surgical procedures



May 12, 1970 w. H. DORMAN 3,511,983

LIGHTING DEVICE FOR DENTAL AND SURGICAL PROCEDURES Filed April 10, 196711 Fig. j

Q I INVENTOR. 5 i f WILLlAM H. DORMAN I -BY WM D. 2 0% F /g. 5

AGENT 3,511,983 LIGHTING DEVICE FOR DENTAL AND SURGICAL PROCEDURESWilliam H. Dorman, Corning, N.Y., assignor to Corning Glass Works,Corning, N.Y., a corporation of New York Filed Apr. 10, 1967, Ser. No.629,663 Int. Cl. A61b 1/06; F21b 7/08, 7/09 US. Cl. 24041.15 2 ClaimsABSTRACT OF THE DISCLOSURE A lighting device for illuminating the oralcavity during dental and surgical procedures, the device having areflector in the basic form of a portion of an ellipsoid of revolutionand a light source located at a focus of the ellipsoid and elongatedalong the axis of revolution of the ellipsoid. The basic ellipsoidalshape of the reflector is modified by the superimposition thereupon of alarge number of contiguous polygonal flutes having reflecting surfacesin the form of portions of circular cylinders.

BACKGROUND OF THE INVENTION This invention relates to lighting devicesof the type generally used by dentists for illuminating the oral cavityof a patient during the performance of dental or surgical procedures.Such devices are generally constructed with reflectors in the form ofportions of ellipsoids of revolution, i.e., surfaces formed by revolvingan ellipse about its major axis. A light source is located on the axisof the ellipsoid at one focus thereof, while the device is oriented suchthat the oral cavity of the patient is in the vicinity of the conjugatefocus. It has been customary to employ in such devices light sourceshaving filaments elongated in directions transverse to the axis of thereflector. Due to the transverse extent of the filament, a light patternof sufficient width has been formed in the area of the conjugate focus.

Inasmuch as a light filament which is elongated in an axial directionwith respect to a reflector extends only a small distance in transversedirections, the illuminated pattern produced at the conjugate focus of areflector by an axially oriented filament is substantially less thanthat produced by a transversely oriented filament. It is, therefore,necessary to modify the basic ellipsoidal shape of the reflector whensuch reflector is used with an axially oriented filament. Accordingly,it is an object of the present invention to provide a dental lightingdevice having a reflector of the common ellipsoidal configuration, buthaving superimposed thereupon a configuration which permits lightemanating from .an axially oriented filament at the principal focus ofthe reflector to be spread by an amount sufficient to illuminate auseful area at the conjugate focus of the reflector.

SUMMARY OF THE INVENTION According to the invention, a dental lightingdevice of the conventional type is provided with an axially orientedfilamentary light source. In order to form a light pattern of usefuldimensions at the conjugate focus of the reflector, the basicellipsoidal configuration of the reflector is modified by thesuperimposition thereon of a plurality of polygonal flutes, each flutehaving a surface in the form of a portion of a cylinder, the axis of thecylindrical surface being in a vertical plane generally parallel to themajor axis of the ellipsoid. Due to the horizontal curvature of theflutes, light emanating from the unit is spread horizontally by anamount greater than the vertical spread of the light, thereby providinga horizon- Patented May 12, 1970 tally elongated pattern of illuminationat the conjugate focus of the reflector.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front elevational view of adental lighting device according to the invention.

FIG. 2 is a sectional view taken on line 22 of FIG. 1.

FIG. 3 is an enlarged perspective view showing the cylindrical flutesemployed on the reflector of FIGS. 1 and 2.

FIG. 4 is a view similar to that of FIG. 3 illustrating an alternativeflute configuration.

FIG. 5 is a front elevational view of an alternative form of flute.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In its preferred embodiment,the lighting device of the invention comprises a glass reflector 10 inthe form of a portion of an ellipsoid of revolution. The ellipsoid isformed by rotating an ellipse about its major axis, indicated by brokenline AA in FIG. 2 of the drawing. Axis AA passes through principal focusB and conjugate focus C of the ellipse. As used herein the termprincipal focus refers to the focus nearer the reflector. A light source12 has its filament 14 elongated along axis AA and located with itscenter generally at principal focus B. A reflective coating 16 coversthe inner surface of reflector 10. Another reflective coating 18 coversthe outer surface of the outer end of light source 12 in order toprevent the escape of light rays directly from the light withoutreflection by the reflector. The end of the light source is preferablyin the form of a portion of a sphere having its center in the vicinityof the center of filament 14, such that reflective coating 18 directslight back past the filament and against reflective coating 16.

Since filament 14 is located at the principal focus of the ellipsoidalreflector surface, light emitted therefrom is reflected by the reflectorin the general direction of conjugate focus C. If the filament were apoint, all the light falling directly upon the reflector would bereflected precisely through point C. However, since the filament has afinite length and width, only a small part of the light emittedtherefrom can be considered to emanate precisely from the principalfocus. Accordingly, only a small amount of light is reflected preciselythrough the conjugate focus, all remaining light being directed aroundthe conjugate focus in a pattern which is dependent upon the shape andorientation of the filament. When a transversely oriented filament isused, this pattern, or source spread, from an ellipsoidal reflector maybe suflicient to provide illumination of the oral cavity. However, whenan axially oriented filament is used, the average angle subtended at thereflector surface by light rays originating at each end of the filamentand falling on a point on the reflector is substantially less than theaverage such angle produced by a transversely oriented filament. Thatis, when viewed from points on the reflector surface, the averageangular extent of the filament is less for an axially oriented filamentthan for a transversely oriented filament. Accordingly, in order toincrease the dimensions of the light pattern produced at the conjugatefocus by an axially oriented filament, the basic ellipsoidalconfiguration of the reflector is modified according to the presentinvention by the superimposition thereon of a large number of flutes 20in the form of portions of circular cylinders. The lighting device isoriented such that the axes of the cylindrical surfaces are in verticalplanes which are generally parallel to axis AA, that is, the axes of thecylindrical surfaces are in planes which are parallel to one another.Accordingly, the horizontal curvature of the flutes causes lightreflected thereby to be spread horizontally. Since the flutes aresubstantially flat in vertical cross-section, the vertical extent of thepattern of light at the conjugate focus resulting from source spread isgreater than that which would be produced by the basic ellipsoidalreflector, which is concave in vertical cross-section.

Due to the fact that the reflector is elongated in the horizontaldirection, i.e., its width is greater than its height, the flutes nearthe peripheries of the lateral edges of the reflector are farther fromthe light source than are the flutes near the upper and lowerperipheries of the reflector. Since source spread is greater for lightreflected from areas on the reflector near the light source than forlight reflected at more remote areas on the reflector, in an alternativeembodiment of the invention, due to the fact that greater spreadingpower is required at greater distances from the light source, thecurvatures of the cylindrical flutes may increase with increasingdistance from the light source.

Although flutes 20 have been illustrated as being convex, they mayalternatively be made in the form of concave cylindrical surfaces, inwhich case light rays striking the flutes will be reflected in a mannerso as to cross one another and subsequently diverge, producing thenecessary spread. Such alternative configuration is illustrated byflutes 22 of FIG. 4. Similarly, the polygonal shape of the cylindricalsurfaces need not be square as illustrated in the preferred embodiment,but may be of other forms, such as hexagonal flutes 24, illustrated inFIG. 5.

Reflecting coatings 16 and 18 may be any conventional silver or aluminumcoatings; however, it has been found that a vacuum deposited coatinghaving the ability to transmit infrared radiation while reflectingvisible light is particularly advantageous when applied to the reflectorflutes. Thus, coating 16 may be a standard dichroic coating such as thecold mirror coating obtainable from Optical Coating Laboratories, Inc.

According to a preferred embodiment of the invention, reflector may bean end portion of an ellipsoid of revolution having its principal focusapproximately 2.27 inches from the reflector when measured along theaxis thereof. The height of the reflector may be 8 inches and the width9 inches. Filament 14, which has its center at the principal focus mayextend along the axis of the reflector by approximately 0.375 inch.Flutes 20 may be square in plan view and approximately 0.4 inch on eachside and may have a radius of curvature of approximately 2.5 inches. Theeccentricity of the ellipse is such that the conjugate focus isseparated from the principal focus by approximately 36.6 inches. Anilluminated area approximately 3.5 by 9 inches will result.

The foregoing description has been provided solely as that of preferredembodiments of the invention. Accordingly, it is recognized that variouschanges and modifications may be made without departing from the spiritand scope of the invention.

I claim:

1. A lighting device useful for illuminating the oral cavity duringdental and surgical procedures, said device comprising:

a concave reflector comprising a glass body having a surface in thegeneral form of a portion of an ellip soid of revolution about an axis,

said reflector being located on said axis and extending transverselytherefrom,

a plurality of rows of polygonal flutes superimposed on the concavesurface of said reflector,

each said row having a plurality of flutes with each flute having areflecting surface in the form of a portion of a circular cylinder,whose axis generally lies Within a common plane with an axis of anadjacent cylinder, taking into consideration the curvature of thereflector,

said rows of circular cylinders having a plurality of contiguous axeslying in vertical planes generally parallel to said axis of revolution,

a light source elongated along said axis of revolution at the focus ofsaid ellipsoid of revolution nearer said reflector, and

a concave reflecting shield disposed in the vicinity of said lightsource between said light source and the conjugate focus of saidellipsoidal surface so as to direct toward said reflector light fromsaid light source which would not otherwise fall thereupon.

2. A lighting device comprising:

a concave reflector in the general form of a portion of an ellipsoid ofrevolution about an axis, said reflector being located generally on saidaxis and extending transversely therefrom,

a plurality of rows of flutes superimposed upon the concave surface ofsaid reflector, each said flute having a concave reflecting surface inthe form of a portion of a cylinder, each row of flutes having alurality of said cylinders lying end to end with axes of adjacentcylinders being contiguous, adjacent end portions of said cylindersabutting one another to form continuous reflecting surface portionsalong the vertical extent of said concave surface, the cylinders in eachrow of flutes having axes lying in lanes generally parallel to such axesin an adjacent row, and

a light source located longitudinally along said axis of revolution atthe focus of said ellipsoid of revolution nearer said reflector, suchthat light emitted by said light source and reflected by said reflectoris directed by said reflector in the general direction of the conjugatefocus of said reflector to form a transversely extending pattern oflight.

References Cited UNITED STATES PATENTS 2,059,033 10/1936 Rivier 24041.352,060,588 11/1936 Ogden 240 41.35 2,294,007 8/ 1942 Trautner 2404l.35

387,430 8/ 1888 Marshall 240103 1,535,985 4/1925 Clark 240-41362,437,516 3/1948 Greppin 240l03 XR 2,540,577 2/ 1951 Greppin 2401.4 XR3,255,342 6/1966 Seitz et al. 240l.4

FOREIGN PATENTS 667,539 6/ 1929 France.

NORTON ANSHER, Primary Examiner R. P. GREINER, Assistant Examiner U.S.Cl. X.R.

